Approximately 13.5% of known causes of global warming come from agriculture (PCC 2007) and the contribution of aquaculture production due to excess undigested nutrients is significant and must be verified. When fed, they use the nutrients provided for maintenance, growth and production purposes, but beyond the needs of the fish, excess nutrients are flushed out, depleting water quality parameters, increasing the production costs, ammonia concentration and invariably has ecological consequences. Fish get energy from protein. and non-protein sources, but the use of protein energy is wasteful from a nutritional, economic and ecological point of view (Manjappa et al 2002). Energy utilization and metabolism of carbohydrate or lipid sources in fish vary depending on the species, age group, composition of the fish's enzyme profile, and the source or origin of the nutrient. There is a delicate balance between the different nutrients provided to fish in terms of protein. energy ratio and the ability of the fish to efficiently use nutrients from these sources (Manjappa et al 2002, Peres and Oliva-Tees...